TY - JOUR
T1 - Consistent fractionation of13C in nature and in the laboratory
T2 - Growth-rate effects in some haptophyte algae
AU - Bidigare, Robert R.
AU - Fluegge, Amim
AU - Freeman, Katherine H.
AU - Hanson, Kristi L.
AU - Hayes, John M.
AU - Hollander, David
AU - Jasper, John P.
AU - King, Linda L.
AU - Laws, Edward A.
AU - Milder, Jeffrey
AU - Millero, Frank J.
AU - Pancost, Richard
AU - Popp, Brian N.
AU - Steinberg, Paul A.
AU - Wakeham, Stuart G.
PY - 1997
Y1 - 1997
N2 - The carbon isotopic fractionation accompanying formation of biomass by alkenone-producing algae in natural marine environments varies systematically with the concentration of dissolved phosphate. Specifically, if the fractionation is expressed by ε≈ δe - δp, where δe, and δp are the δ13C values for dissolved CO2 and for algal biomass (determined by isotopic analysis of C37 alkadienones), respectively, and if Ce is the concentration of dissolved CO2, μmol kg-1, then b = 38 +160*[PO4], where [PO4] is the concentration of dissolved phosphate, μM, and b = (25 - εP)Cε. The correlation found between b and [PO4] is due to effects linking nutrient levels to growth rates and cellular carbon budgets for alkenone-containing algae, most likely by trace-metal limitations on algal growth. The relationship reported here is characteristic of 39 samples (r2 = 0.95) from the Santa Monica Basin (six different times during the annual cycle), the equatorial Pacific (boreal spring and fall cruises as well as during an iron-enrichment experiment), and the Peru upwelling zone. Points representative of samples from the Sargasso Sea ([PO4] ≤ 0.1 μM) fall above the b = f[PO4] line. Analysis of correlations expected between μ(growth rate), εP, and Ce shows that, for our entire data set, most variations in εp result from variations in μ rather than Ce. Accordingly, before concentrations of dissolved CO2 can be estimated from isotopic fractionations, some means of accounting for variations in growth rate must be found, perhaps by drawing on relationships between [PO4] and Cd/Ca ratios in shells of planktonic foraminifera.
AB - The carbon isotopic fractionation accompanying formation of biomass by alkenone-producing algae in natural marine environments varies systematically with the concentration of dissolved phosphate. Specifically, if the fractionation is expressed by ε≈ δe - δp, where δe, and δp are the δ13C values for dissolved CO2 and for algal biomass (determined by isotopic analysis of C37 alkadienones), respectively, and if Ce is the concentration of dissolved CO2, μmol kg-1, then b = 38 +160*[PO4], where [PO4] is the concentration of dissolved phosphate, μM, and b = (25 - εP)Cε. The correlation found between b and [PO4] is due to effects linking nutrient levels to growth rates and cellular carbon budgets for alkenone-containing algae, most likely by trace-metal limitations on algal growth. The relationship reported here is characteristic of 39 samples (r2 = 0.95) from the Santa Monica Basin (six different times during the annual cycle), the equatorial Pacific (boreal spring and fall cruises as well as during an iron-enrichment experiment), and the Peru upwelling zone. Points representative of samples from the Sargasso Sea ([PO4] ≤ 0.1 μM) fall above the b = f[PO4] line. Analysis of correlations expected between μ(growth rate), εP, and Ce shows that, for our entire data set, most variations in εp result from variations in μ rather than Ce. Accordingly, before concentrations of dissolved CO2 can be estimated from isotopic fractionations, some means of accounting for variations in growth rate must be found, perhaps by drawing on relationships between [PO4] and Cd/Ca ratios in shells of planktonic foraminifera.
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U2 - 10.1029/96GB03939
DO - 10.1029/96GB03939
M3 - Article
C2 - 11540616
AN - SCOPUS:0030609185
SN - 0886-6236
VL - 11
SP - 279
EP - 292
JO - Global Biogeochemical Cycles
JF - Global Biogeochemical Cycles
IS - 2
ER -